Heater for wrapping machine



6, 1960 M. ZWARYCZ 2,949,001

HEATER FOR WRAPPING MACHINE Filed March 3, 1958 2 Sheets-Sheet 1 ENVENTOR MICHAEL ZWARYCZ ATTORNEY Aug. 1950 M. ZWARYCZ 2,949,001

HEATER FOR WRAPPING. MACHINE Filed March 3, 1958 2 Sheets-Sheet 2 FIG. 4

2? 3 g? INVENTOR 28 MBCHAEL ZWARYCZ ATTORNEY 2,949,001 lafi Patented-Aug- 1960 HEATER ron WRAPPING MACHINE Michael Zwarycz, Wilbraham, Mass., assignor to Crompton & Knowles Packaging Corporation, Holyoke, Mass, a corporation of Massachusetts Filed Mar. '3, 1958, Ser. No. 718,775

8 Claims. (Cl. 53-'141) This invention relates to improvements in package wrapping machinery and more particularly to the heating means which seals the folded flaps of a thermoplastic wrapper.

In a well-known type of wrapping machine the article to be wrapped is pushed upwardly against a sheet of thermoplastic wrapper material and is then forced into a pocket in an indexing head. Folding plates then pass under the package to fold opposite sides of the depending wrapper and a third plate is then advanced under one edge of the package to fold a third part of the wrapper under the package. The indexing head then advances and moves the package onto a stationary table and in doing so causes the remaining depending part of the wrapper to be deflected upwardly under the package to form the fourth flap as the package passes onto the table. During this indexing operation the package is moved over a heater which softens the thermoplastic wrapper sufficiently to permit sticking the various flaps to each other. In the past it has been found that occasionally some of the material of the wrapper will remain on the surface of the heater and this has the effect of causing a so-called pull-back of the trailing flap as the package is moved by the indexing head.

It is an important object of the present invention to provide means for depositing a thin film or layer of a suitable lubricant on the underside of the folded flaps and then transfer the lubricant to the heater as the package is moved over it by the indexing head.

It is a further object of the invention to provide a horizontal hollow porous cylinder or roll containing a lubricant which is in the form of a paste and nonfluid at room temperatures but becomes sufiiciently fluid during operation of the machine to seep through the crevices in the porous cylinder to the periphery thereof and be deposited on the underside of the package. As the indexing head moves the package the cylinder is turned due to contact with the flaps and in this way the film of lubricant is uniformly distributed on the underside of the package.

It is a still further object of the invention to provide a heater in the form of a series of freely rotatable aligned rolls and locate the aforesaid lubricating cylinder at one end of the series. The latter is so placed that the package passes over it first and then movesonto .the rolls to deposit lubricant on the peripheries thereof.

It is a further object ofthe invention to make the aforesaid lubricating cylinder hollow with closed ends, one of the ends being provided with a plug which can be removed for the purpose of inserting the paste-like lubricant into the cylinder. The plug is preferably formed with a gudgeon which cooperates with mountingmeans to enable the cylinder to be rotatable by frictional contact with the package passing over it.

In order that the invention may be clearly understood reference is made to the accompanying drawings which illustrate by way of example the embodiment of the invention-and in which:

Fig. 1 is a plan view of the heater element forming part of the invention,

Fig. 2 is a vertical section on line 22, Fig. 1, the lefthand part only of the figure being in section and the righthand part being in elevation as indicated from the shape of the section line 2-2,

Fig. 3 is a detailed vertical section on line 33, Fig. 1,

Fig. 4 is a diagrammatic plan view showing enough of the wrapping machine and its indexing head to understand the manner of operation of the invention,

Figs. 5 to 9 are diagrammatic views showing successive operations which are performed on the package being wrapped, and

Fig. 10 is a perspective view of the underside of a package showing the manner in which the flaps can be folded thereunder.

Referring first to Fig. 4, the machine has a runway or conveyor 1 along which the package to be wrapped is moved to areceiving station RS under the indexing head 2. The latter is formed in the present instance with five pockets designated at 3 each having depending flanges 4. An elevator 5 is located under the indexing head and in register with the receiving station and after the wrapper W which may be sheet polyethylene, cellophane or other thermoplastic material, has been placed over the package P as shown in Fig. 5, the elevator is lifted to force the package upwardly into the pocket at the receiving or wrapping station to fold the overhanging edges of the Wrapper downwardly around the corresponding sides of the package. Thin plates then move from opposite sides of the package under the latter to fold end flaps under the package after which a third plate 6 is moved from the position shown in Fig. 5 to the position shown in Fig. 6 under the package to fold the left-hand draping edge of the wrapper to form a flap 7. The head 2 is then rotated in a counterclockwise direction over a table 10 to cause the right-hand part of the wrapper, shown depending at 11 in Fig. 6, to be folded up under the carton to form a flap 12, see Fig. 7, as the'package passes over the edge of the table.

Continued movement of the indexing head then moves the wrapped package to the right as indicated in Fig. 7 through the position shown in Fig. 8 to the position shown in Fig. 9, at which time the indexing head brings the package to rest at the sealing station SS, Fig. 4, andtis ready for the next wrapping operation. The flaps on the underside of the package are now in position to be heated to enable them to stick to each other. In the meantime, the plunger 5 has descended for the .next wrapping operation and at a later time another indexing operation of the head 2 will deposit the wrapped and sealed package onto a runway or conveyor 15. The mechanism for intermittently moving the head includes gears 16 and 17 meshing with each other and operated by known mechanism to tum the head.

The matter thus far described is similar to the socalled Model DW and P series of multiformed wrapping machine made by the Wrap-King Division of the Crompton & Knowles Packaging Corporation located in Holyoke, Massachusetts.

In carrying the present invention into effect a support means 20 is mounted in fixed position under table 10 and has right and left angle irons 21 and 22 respectively, see Figs. 1 and 2, secured thereto by belts or the like 23. Side bars 24 are secured by screws 25 to the angle irons 21 and 22. Screws 26 pass through the bars 24 and through bearing plates 27 into a heat conductor or the like 28 whch may be made of any appropriate material, such as aluminum. The heat conductor 28 and the bearing plates 27 are thus held tightly to the side bars 24 by the screws 26 and the latter in turn .are supported by the angle irons and support 20. H

The underside of the heat conductor 28 has depending ribs 30 defining spaces for electric heating elements 31 which are held in position on the underside of the conductor by straps 32 fastened to the ribs by screws 33. A thermostat 34 is provided to regulate the temperature of theheating elements 31. n

The bearing plates 27 are each provided with a plurality of equally spaced upwardly opening bearing pockets 35 which receive the gudgeons 36 of a series of aligned horizontal heater rolls 37 which are substantially parallel and of the same diameter and rotate freely in the open bearing pockets. These rolls may, if desired, be coated with a thin layer of tetrafiuoroethylene (not shown). The top surfaces of these rolls may extend slightly above the plane of the top surface of the table to extend into and maintained in a path traversed by one side of a package as the latter moves from receiving station RS to the sealing station SS.

At one end of the series of rolls 37 between the latter and the receiving station is located a rotating lubricating means which engages the wrapped package and includes a cylinder 40 forming an important part of the present invention. This cylinder is aligned with rolls 37 and is made of small metallic particles compressed together, somewhat in the manner of bronze self-lubricating bearings, so that the cylinder is porous. As seen in Fig. 2, roll 4t) rotates about a horizontal axis, thus maintaining lubricant L evenly distributed between the ends of the roll. The cylinder has a bore 41 running for substantially its full length and has the right-hand end as viewed in Fig. 2 closed and provided with a gudgeon 42. The left-hand end of the cylinder has threaded thereinto a plug 43 provided with a gudgeon 44 to enter one of the open bearing pockets 35. The plug is removable to permit injection into the cylinder of a plastic or grease-like lubricant L which is semi-solid and does not flow at room temperatures and hence cannot seep out through the minute passages in the porous cylinder. When the latter is heated, however, the grease is able to flow through the minute passages and pass out to the surface of the cylinder.

In operation, as the indexing head moves the leading edge of the package to the position shown in Fig. 8 the underside of the flap 12 will rest on the lubricating cylinder and by frictional contact therewith will cause it to rotate as the head 2 indexes. At this time electric power will have been turned on the heating elements 31 sufiiciently long so that heat by conduction has passed up through the conductor 28 and through the walls of the cylinder 40 to make the lubricant therein fluid so that it can flow out to the surface of the cylinder and as the package passes to the right from the position shown in Fig. 8 the cylinder 40 is caused to rotate and deposit a thin film of lubricant on the underside of the flaps folded under the package, see Fig. 10. A suflicient amount of the lubricant will adhere to the flaps so that as the package continues to move over and rotate the rolls 37 the latter will have a thin film of lubricant deposited on their peripheries. All of the rolls 37 will thus be sufliciently coated so that there is no chance that a pull-back" can occur, as mentioned hereinbefore in connection with previously known heaters. The bearing plates may be considered to be mounting means on which rolls 37 and cylinder 40 are rotatably mounted, being held in the pockets 35 by gravity and readily removable therefrom.

Any convenient form of lubricant can be used within the cylinder 40. A lubricant which has been found to operate satisfactorily is one of the silicone pastes or greases made by the Dow-Corning Corporation bearing. the trade name Slipicone. Silicones are inorganic plastic materials having a structure somewhat similar to organic plastics except that in place of carbon atoms silicon and oxygen atoms are arranged in alternations to form for instance a methyl silicon polymer which in the,

4 liquid form may be mixed with a metallic soap to give a grease-like consistency. At room temperature the silicone lubricant is nonflowable but when the heaters 31 have been turned on sufficiently long to develop a heat of 375 to 400 F., the silicone paste or grease becomes sufficiently fluid to pass through the minute spaces left in the roll 40 between the individual metallic parts of which it is made. When the heaters are turned olf the temperature of the rolls and cylinder and also the conductor 28 will drop to room temperature and the lubricant will again become grease-like and be incapable of seeping outwardly from bore 41 to the surface of the roll 40.

From the foregoing it will be seen that the invention sets forth simple means for lubricating the surface of a heater in a package wrapping machine whereby movement of the wrapped package P by the indexing head 2 conveys a film of lubricant from a lubricating means to the surface of the heating means. The lubricating means as shown herein is a hollow cylinder 40 which is engaged and rotated by the advancing package as the latter moves from the receiving station RS to the sealing station S5. The cylinder deposits a film of lubricant on the bottom of the package which then distributes the lubricant over rolls 37 of the heater due to movement of the package by the indexing head. The lubricating cylinder is porous and contains a supply of the lubricant L which congeals at room temperatures so that it will not flow through the cylinder but becomes fluid when the heater is in operation and flows out to the surface of the cylinder where it can be picked up by the folds on the underside of the wrapped package. Also, the lubricating cylinder has a removable plug for convenience in renewing the supply of the lubricant in the bore of the cylinder and this plug has a gudgeon which assists in mounting the cylinder for rotation. The cylinder and rolls are preferably, though not necessarily, of the same diameter and have their upper surfaces aligned so that all the rotating parts will be turned by movement of the package over them. The lubricant used is preferably a silicone which may be basically of the fluid type mixed with a metallic soap so that it becomes capable of flowing through the small passages on the cylinder 40 when heated. The invention, however, is not limited to this specific type of lubricant.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

1. In a heater for a wrapping machine which places a thermoplastic wrapper around a package, a series of aligned heat conducting rolls, a porous lubricating cylinder aligned with the series of rolls and containing a Inbricant normally nonflowing at room temperature, but capable when heated of flowing through the cylinder to the outer surface thereof, means mounting said rolls and cylinder for rotation, and heater means adjacent to said rolls and cylinder to heat the rolls to enable them to heat seal the wrapper and also heat the lubricant in the cylinder to a temperature at which it can flow to the surface of the cylinder and be carried by the wrapper from the cylinder to said rolls.

2. The heater set forth in claim 1 wherein the mounting means provides upwardly opening hearings in which the rolls and cylinder are held by gravity and the heater means is below the rolls and cylinder.

3. The heater set forth in claim 1 wherein the cylinder is porous and has a hollow bore which contains the lubricant.

4. The heater set forth in claim 1 wherein the cylinder is at one end' of the series of rolls so that a package moving from the cylinder toward and over the rolls will lubricate the latter by lubricant deposited on the package by the cylinder.

5. The heater set forth in claim 1 wherein the cylinder is porous and hollow and is fittedat one end thereof with a removable plug to permit filling of the cylinder with lubricant.

6. The heater unit set forth in claim 5 wherein the plug is provided with a gudgeon to provide for rotation of the cylinder on said mounting means.

7. In a wrapping machine operating to place a thermoplastic wrapper around a package at a wrapping station and then move the package to a sealing station, to tatable lubricating means to engage said package and effective to place a film of lubricant on the packages as the latter move from the wrapping station toward the sealing station, and a heater at the latter station on which the lubricant is deposited by the package as the latter moves to the sealing station.

8. In a wrapping machine to operatively place a thermoplastic wrapper around a package movable from a wrapped package receiving station to a wrapper heat sealing station having a series of rotatable heating rolls to heat seal the wrapper in position around said package, a hollow rotatable porous cylinder between said receiving station and said heating rolls and containing a lubricant for seepage through the pores of said cylinder to the periphery thereof, said cylinder and said rolls being rotatably mounted so as to have their peripheries extend into and maintained in a path traversed by one side of said package to engage said rolls when the package moves from said receiving station to said sealing station, and means to move said package along said path to cause said one side to first engage and rotate said cylinder to effect a deposit of lubricant on said wrapper from said periphery and then to engage and rotate the heating rolls to deposit a thin film of lubricant on the peripheries thereof from said wrapper to prevent the latter from sticking to the heating rolls while said package is moving therealong during a heat scaling operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,347,439 Shea Apr. 25, 1944 2,650,643 Fuchs Sept. 1, 1953 2,749,692 Conti June 12, 1956 FOREIGN PATENTS 277,200 Great Britain Sept. 15, 1927 

